How often should the air tanks be drained?
- Monthly
- Weekly
- During periodic maintenance
- Daily ✓
Answer: D. Daily
The air tanks should be drained daily.
Why this is the answer
The handbook says all reservoirs should be drained daily, and it places draining the reservoirs in the pre-trip inspection routine. It also explains that compressor air carries water vapor that condenses in the supply reservoir, and that oil and carbon particles can mix with this water to form sludge. Draining the reservoirs helps keep that sludge from getting into air valves and other brake parts. Because the handbook ties draining to daily inspection and the manufacturer recommendation, daily is the answer.
Why the other answers are wrong
- A. Monthly — Monthly leaves the tanks undrained far longer than the daily draining the handbook calls for, so water and sludge can build up between drains.
- B. Weekly — Weekly is still less often than the daily draining stated in the handbook, so it does not match the recommended routine.
- C. During periodic maintenance — Waiting until periodic maintenance is not the daily draining the handbook describes and lets contaminants collect between services.
Remember it
Think of draining the reservoirs as part of getting the vehicle ready each day, not a once-in-a-while shop job.